1. Field of the Invention
This invention relates to machine tools and more particularly to turret punched machine tools.
2. Prior Art
Machine tools such as turret punches having upper and lower revolving turrets are well known to the art. Such devices usually include a machine frame which is C shaped with a upper turret depending from the top of the C at the opening of the C and the lower turret aligned with the upper turret extending from the bottom of the C at the opening, the upper and lower turrets having a working clearance there between.
Normally, such machines have a plurality of punches carried by the rotatable upper turret and a plurality of dies carried by the lower turret. Indexing of the two turrets will bring any one of a number of corresponding dies and punches into an operating position, normally at the front of the opening. Thereafter a workpiece is inserted between the turrets at the operating position and the machine is activated to force the punch through the workpiece into the die.
In order to support the workpiece, a table member surrounds the lower turret and has a table top on a level with a top of the lower die turret. The workpiece is then moved into the area between the upper and lower turrets and is partially supported on the worktable.
Since the table top extends outwardly beyond the turret, it is extremely difficult to change the dies. The upper turret is normally surrounded by a shroud which is removable or which can be opened. However due to the necessity of making the worktable sufficiently rigid to support the workpiece, removal of the worktable is quite difficult. While segmenting the table would allow a segment to be removed, this would, in many embodiments, require a two man job, to carry away the heavy table segment to give access to the lower turret dies and would complicate the die changing process.
In many such machines the die is removed from the periphery of the lower turret by removing fastening means at the periphery of the lower turret and thereafter withdrawing the die. This may require a radial clearance of a number of inches in order to lift the die away from the turret.
In addition, dies are normally removed in association with a punch and it would therefore be convenient if both the dies and the punches could be removed at a common peripheral section of the turrets.
Further, dies and punches are often removed in multiples and it would therefore be an advantage to provide a temporary work surface for use by the person removing the tools to store parts thereof at a spot convenient to his reach when working on the turrets.